Jock Doc

Sac behind elbow can fill with fluid, causing big bump

Q: Two weeks ago, my mother noticed a large bump on the back of her right elbow that keeps increasing in size. She did not fall or remember hurting herself. It is about the size of an egg but it does not hurt. My mother has normal motion of her elbow. We are worried that it could be something like a tumor or a torn muscle. Who should she see for this?

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Dr. Harlan Selesnick

A: Between the skin and the bone on the back of the elbow sits a sac known as the olecranon bursa. If traumatized, this sac can fill with fluid and become very large. If the fluid collection is small, the doctor can treat it with anti-inflammatory medication and a compression wrap. If the fluid collection is large, the fluid can be drained and cortisone can be injected into the sac to decrease the risk of recurrence.

It is important that your mom not puncture or scratch the bursa as it is prone to infection, which could make treatment more complicated.

Rarely does this condition need surgery. I recommend she see an orthopedic surgeon to confirm the correct diagnosis and initiate treatment as well as reassure your mother that there is nothing really bad.

Dr. Harlan Selesnick is team physician of the Miami Heat and director of Miami Sports Medicine Fellowship, Doctors Hospital. Send your questions to